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排序方式: 共有190条查询结果,搜索用时 35 毫秒
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Dolashki A Abrashev R Stevanovic S Stefanova L Ali SA Velkova L Hristova R Angelova M Voelter W Devreese B Van Beeumen J Dolashka-Angelova P 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(3):975-983
The fungal strain Aspergillus niger produces two superoxide dismutases, Cu/Zn-SOD and Mn-SOD. The primary structure of the Cu/Zn-SOD has been determined by Edman degradation of peptide fragments derived from proteolytic digests. A single chain of the protein, consisting of 153 amino acid residues, reveals a very high degree of structural homology with the amino acid sequences of other Aspergillus Cu/Zn-SODs. The molecular mass of ANSOD, measured by MALDI-MS and ESI-MS, and calculated by its amino acid sequence, was determined to be 15821 Da. Only one Trp residue, at position 32, and one disulfide bridge were identified. However, neither a Tyr residue nor a carbohydrate chain occupying an N-linkage site (-Asn-Ile-Thr-) were found. Studies on the temperature and pH dependence of fluorescence, and on the temperature dependence of CD spectroscopic properties, confirmed that the enzyme is very stable, which can be explained by the stabilising effect of the disulfide bridge. The enzyme retains about 53% of its activity after incubation for a period of 30 min at 60 degrees C, and 15% at 85 degrees C. 相似文献
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Clustering has become one of the fundamental tools for analyzing gene expression and producing gene classifications. Clustering
models enable finding patterns of similarity in order to understand gene function, gene regulation, cellular processes and
sub-types of cells. The clustering results however have to be combined with sequence data or knowledge about gene functionality
in order to make biologically meaningful conclusions. In this work, we explore a new model that integrates gene expression
with sequence or text information. 相似文献
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Angelov B Angelova A Papahadjopoulos-Sternberg B Lesieur S Sadoc JF Ollivon M Couvreur P 《Journal of the American Chemical Society》2006,128(17):5813-5817
Supramolecular three-dimensional self-assembly of nonlamellar lipids with fragments of the protein immunoglobulin results in a bicontinuous cubic phase fragmented into nanoparticles with open water channels (cubosomes). The structure of the diamond-type cubic nanoparticles is characterized experimentally by freeze-fracture electron microscopy, and it is mathematically modeled with nodal surfaces emphasizing the fluid-like undulations of the cubosomic interfaces. Based on scaling-up and scaling-down approaches, we present stable and intermediate-kind nanoparticles resulting from the cubosomic growth. Our results reveal the smallest stable diamond-type cubosomic entity that can serve as a building block of more complex nanostructured fluid drug delivery vehicles of therapeutic proteins. The evidence presented for lipid-bilayer undulations in the surface region of the protein/lipid cubosomes could have important consequences for possible applications of these hierarchically organized porous nanoparticles. 相似文献
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Antonio García Martínez Santiago de la Moya Cerero Beatriz Lora Maroto 《Tetrahedron》2004,60(42):9447-9451
The competitive pathway timing for the previously described unexpected bromo-assisted Beckmann fragmentation of 7-anti-bromo-3,3-dimethyl-2-oxonorbornane-1-carboxamide has been investigated. It is concluded that this unusual process is activated by a synergic effect exerted by both the C(7)-anti-bromo and C(1)-aminocarbonyl groups. The effect consists in a specific intramolecular activation of the bromo-assistance by the bridgehead aminocarbonyl group. 相似文献
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